Environmental control systems are available which can control environmental parameters. An example environmental control system is a heating ventilation and air conditioning (HVAC) system, which may comprise one or more devices which are operable to heat, ventilate and/or air condition a premises. In some cases, HVAC systems or environmental control systems may be operable to provide only heating, ventilation air conditioning or humidity control, rather than a combination. Environmental control systems may comprise environmental control devices for controlling the environmental parameters, e.g. boilers, radiators, central heating systems, air conditioning units or dehumidifiers and/or humidifiers.
It is possible to provide control commands for environmental control systems by programming a schedule into a thermostat at a premises, for example by pressing buttons or interacting with a touch screen on the thermostat. Such a schedule may comprise one or more user-programmable environmental characteristic setpoints and corresponding time periods, during which an environmental characteristic (or parameter) of the premises should be maintained above or below the setpoint. For example, a user may wish the temperature to be maintained between 18° C. and 22° C. between 7 am and 9 am each day. Alternatively, or additionally, a user may wish the humidity to be maintained below, e.g. 45% relative humidity (RH) throughout the day, except when the user is on vacation, when humidity levels may be allowed to rise to 50% RH in order to save energy. The thermostat may then provide commands to appliances such as a boiler, central heating system, air conditioning unit or (de-)humidifier based on measured or sensed environmental characteristics (such as the temperature or humidity) in order to maintain these characteristics within (or influence the variables towards) the user-determined setpoints.
Using an environmental control system with a thermostat at the premises that can be programmed by the user does not allow control to be optimised if the user's behaviour deviates from normal or expected behaviour, for example, if the user leaves or arrives home earlier than usual.
Sending a remote control message in a mobile telephone to control a device, either by text (SMS) message or a dedicated application is known.